Composite data type molecule

While atomic coordinates form the fundamental structure of a molecule, many methods prefer to represent a three-dimensional structure as a surface or a shape. Of course, these are ultimately computed from the atomic coordinates and perhaps atomic partial charges. It may be possible to represent these molecular surfaces or shapes as an array of three-dimensional coordinates. These could be stored as a column in the database analogous to the array of atomic coordinates. It might be necessary to create another data type, perhaps a composite data type, to store molecular surfaces or shapes. Once these representations are stored, they can be used in new SQL functions to assist in searching based on molecular surface or shape. 

You can also use the mole concept to calculate the empirical formula of a compound using the percentage composition data for that compound — the percentage by weight of each element in the compound. (The empirical formula indicates the different types of elements in a molecule and the lowest whole-number ratio of each kind of atom in the molecule. See Chapter 7 for details.)... 

Table 28 presents structural characteristics of compounds with X Me ratios between 6 and 5 (5.67, 5.5, 5.33, 5.25). According to data provided by Kaidalova et al. [197], MsNbsC Fu type compounds contain one molecule of water to form M5Nb303Fi4-H20, where M = K, Rb, Cs, NH4. Cell parameters for both anhydrous compounds [115] and crystal-hydrates [197] were, nevertheless, found to be identical. Table 28 includes only anhydrous compound compositions because IR absorption spectra of the above compounds display no bands that refer to vibrations of the water molecule... 

The data presented in Table 3, which includes the amino acid composition of baker s yeast and Candida krusei cytochrome c for comparison, show that Ustilago and Neurospora cytochrome c contain the same number of total residues. In seven instances, the number of residues of a particular amino acid/mole are identical. Thus, even in the absence of a sequence for the Ustilago cytochrome it can be concluded that this protein, unlike the siderochromes, has suffered little alteration in the progression from the Ascomycetes to the Basidiomycetes. This can be ascribed to the varying function of the two types of molecules. Cytochrome c must fit into a relatively specific slot bounded by a reductase and an oxidase and it has hence evolved much more slowly than the more freely acting transport agents where the specificity constraints are less demanding. 

The number of studies on the health effects of fullerenes and carbon nanotubes is rapidly increasing. However, the data on their toxicity are often mutually contradictory. For example, the researchers from universities of Rice and Georgia (USA) found that in aqueous fullerene solutions colloidal nano-C particles were formed, which even at low concentration (approximately 2 molecules of fullerene per 108 molecules of water) negatively influence the liver and skin cells [17-19]. The toxicity of this nano-C aqueous dispersion was comparable to that of dioxins. In another smdy, however, it was shown that fullerene had no adverse effects and, on the contrary, had anti-oxidant activity [20]. Solutions of prepared by a variety of methods up to 200 mg/mL were not cytotoxic to a number of cell types [21]. The contradiction between the data of different authors could be explained by different nano-C particles composition and dispersion used in research. 

Tables 2.5a,b provide a comprehensive list of guest molecules forming simple si and sll clathrate hydrates. The type of structure formed and the measured lattice parameter, a, obtained from x-ray or neutron diffraction are listed. Unless indicated by a reference number, the cell dimension is the 0°C value given by von Stackelberg and Jahns (1954). Where no x-ray data exists, assignment of structure I or II is based on composition studies and/or the size of the guest molecule. Tables 2.5a,b also indicate the year the hydrate former was first reported, the temperature (°C) for the stable hydrate structure at 1 atm, and the temperatures (°C) and pressures (atm) of the invariant points (Qi and Q2). Both cyclopropane and trimethylene oxide can form si or sll hydrates. Much of the contents of these tables have been extracted from the excellent review article by Davidson (1973), with updated information from more recent sources (as indicated in the tables).

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